The present invention relates to an information reproducing/recording apparatus having compatibility for recording and reproducing different types of optical discs, and an optical disc discriminating method.
In recent years, standards for HDDVD and Blu-ray disc (BD) using a 405 nm wavelength blue-violet laser for reading/recording with a storage capacity improved substantially in comparison with DVD have been added to the conventional CD and DVD standards.
Besides, there are also standards for a dual disc (also called “hybrid disc”) having both characteristics of different standards of CD and DVD and for a LabelFlash disc having a discoloration layer, which is discolored by heat or light, formed integrally on a side of a substrate opposite to a recording layer to enable to form a labeling surface on the side opposite to the recording layer by emitting a laser beam to the discoloration layer.
Accordingly, an information reproducing/recording apparatus having compatibility with recording or reproducing of different types of optical discs needs to discriminate a type of optical disc at the time of recording on an optical disc or reproducing the optical disc.
For example, Japanese Patent Laid-Open No. 11-86338 describes a discriminating method of a hybrid disc in a reproducing apparatus for an optical disc which has discrimination information about a disc type recorded in a designated recording region, comprising a step of irradiating a CD laser beam onto the optical disc set on a DVD reproducing apparatus, a step of checking whether the discrimination information is recorded in the designated recording region when data is read from the optical disc, and a step of recognizing the optical disc as a hybrid disc when the discrimination information is recorded in the designated recording region.
Japanese Patent Laid-Open No. 2007-226869 describes an optical disc apparatus that an optical pickup is vertically moved to detect a focus error signal, a focus drive height h is detected at a position where a focus error signal becomes maximum from a time when the focus error signal has exceeded a particular level to a next time when the focus error signal exceeds a particular level, and when a disc having two or more layers is set, it is discriminated with high precision what disc is the set optical disc according to a distance d between the plural focus drive heights detected by the above method, thereby wasteful start processing is eliminated.
Japanese Patent Laid-Open No. 2004-206845 describes an optical disc apparatus which discriminates a label surface to which an optical pickup is faced according to a waveform of a focus error signal which appears at the time of focus search prior to the focus control.